The present invention relates generally to memory devices and, more particularly, to a folding USB flash drive or memory storage device that is specifically adapted to be fabricated in an unfolded state using a thin, flexible substrate for reduced manufacturing and testing costs but which is then oriented into a folded state and assembled into a compact housing body resulting in a memory storage device having increased memory capacity.
Included in the prior art are many configurations of digital memory devices that are based on non-volatile semiconductor flash memory. Such digital memory devices typically contain one or more flash memory semiconductor integrated circuits (IC) or packages, a controller which may be integrated with the flash memory semiconductor IC, a printed wiring board substrate (PWB) and some passive components 54.
One such processor digital memory device is a USB flash drive. Such flash drives utilize flash memory which, as was earlier mentioned, is non-volatile in that no power is required in order to maintain the stored information. Unlike dynamic random access memory (DRAM), wherein all data that is in a computer's DRAM memory is lost when the computer is turned off, non-volatile memory retains data even when not powered. For example, when a flash memory device is removed from a personal data assistant (PDA), all data is maintained in the flash memory device.
It is well known that the flash memory devices are rewritable. More specifically, USB flash drives enable users to write and erase entire contents of the memory device many times. In fact, the write-cycle endurance of many flash drives enables users to rewrite the entire contents of the flash drive well beyond the life of most electronic devices with which the flash drive is used. In addition, flash memory drives can be used repeatedly with no degradation in quality. Such flash memory drives typically include a flash controller which automatically locks out bad memory cells and moves data to other sections in the memory device in order to avoid data corruption.
Other advantages of flash memory drives include the ability to function within a wide operating temperature and humidity range. The rate at which data can be stored and retried in flash memory drives is generally faster than many other memory products such as CD-ROMs and other portable storage devices such as 3½ inch floppy disks, specialized high capacity floppy disks, and tape drives. This is due in part to the fact that flash memory drives are generally solid state and do not include any moving parts.
Additionally, flash memory drives are non-magnetic and therefore not susceptible to damage from magnetic devices. Other benefits of flash memory drives are lower power consumption for longer battery life in a host device, ease of recognition by the host computer when the flash memory device is connected to the computer, the ability to connect or disconnect the flash memory device to the host computer without first powering off and then powering on the computer.
Additional important advantages of flash memory drives is their small size. Commonly referred to as pen drives due to their similarity to the length of a writing pen, many flash memory drives have the capability for storing up to one giga-bite of data. For this reason, flash memory drives are a popular device for transferring data from one device to another. Some flash memory drives are shaped and sized to be connected to a key chain. Alternatively, some flash memory drives have a clip such that a user can clip the flash memory drive onto a shirt pocket.
Despite the above mentioned advantages of high storage capacity, fast data transfer rates, and optional security such as password-protected access, it is still desirable that flash memory drives have a further increased capacity in order to keep pace with the ever increasing memory demands of new electronic devices. Furthermore, it is desirable that the flash memory drives provide such increased memory capacity at a reduced manufacturing cost. More specifically, it is desirable to reduce the cost for assembly and testing of the flash memory drives. At the same time, it is desirable to keep the size of the flash memory device small as most consumers appreciate the convenience, portability and compactness of flash memory drives of the prior art.
As can be seen, there exists a need in the art for a flash memory drive that offers the convenience of high storage capacity and a compact size but which may be manufactured at a reduced cost. Furthermore, there exists a need in the art for a flash memory drive that incorporates the universal serial BUS (USB) interface that is connectable to a wide range of devices such as PC's, PDA's, and MP3 players. In addition, there exists a need in the art for a flash memory drive that conveniently packaged so that a user may transport the flash memory drive by clipping to a shirt pocket or carrying on a key chain.